1. Field of the Invention
The present invention relates to an interactive display system having an interactive surface, at which surface at least two contact points can be detected and distinguished between.
2. Description of the Related Art
A typical example of an interactive display system is an electronic whiteboard system. An electronic whiteboard system typically is adapted to sense the position of a pointing device or pointer relative to a working surface (the display surface) of the whiteboard, the working surface being an interactive surface. When an image is displayed on the work surface of the whiteboard, and its position calibrated, the pointer can be used in the same way as a computer mouse to manipulate objects on the display by moving a pointer over the surface of the whiteboard.
A typical application of an interactive whiteboard system is in a teaching environment. The use of interactive whiteboards improves the teaching productivity and also improves student comprehension. Such whiteboards also allow use to be made of good quality digital teaching materials, and allow data to be manipulated and presented using audio visual technologies. A typical construction of an electronic whiteboard system comprises an interactive display forming the electronic whiteboard, a projector for projecting images onto the display, and a computer system in communication with the electronic whiteboard for generating the images for projection, running software applications associated with such images, and for processing data received from the display associated with pointer activity, such as the location of the pointer on the display surface. In this way the computer system can control the generation of images to take into account the detected movement of the pointer on the interactive surface.
It is known in the art of interactive display systems to adapt an interactive surface to allow detection of the presence of two contact points at an interactive surface and to distinguish between them. The ability to detect and distinguish between two contact points allows for the control of an interactive display system to be improved. An example of such an improved interactive display system is described in United Kingdom Patent Application Publication No. 2443010 in the name of Promethean Limited.
It is an aim of the invention to provide improvements to an interactive display system including an interactive surface which is adapted to detect and distinguish the presence of at least two contact points on the interactive surface.